FIB-4 Index Discriminates Long-Term Mortality Better than Chest CT Severity Scores in Severe COVID-19

Coronavirus disease 2019 (COVID-19) causes systemic inflammation and multi-organ injury that may persist beyond the acute illness. The Fibrosis-4 (FIB-4) index and the aspartate aminotransferase-to-platelet ratio index (APRI) are inexpensive liver fibrosis scores whose long-term prognostic value after COVID-19 pneumonia is undefined. In this single-center retrospective study, 101 adults hospitalized with severe COVID-19 pneumonia were followed for three years. FIB-4, APRI, and the chest computed tomography (CT) severity score were derived from admission data. Discrimination was quantified by the area under the receiver operating characteristic curve (AUC) and compared with the DeLong test; nested logistic regression models tested whether FIB-4 added prognostic information beyond age. Fifty-seven patients (56.4%) died, 39 in hospital and 18 after discharge. Admission FIB-4 was higher in non-survivors (median 3.0 vs. 1.5; p < 0.001), whereas APRI did not differ. FIB-4 showed superior prognostic accuracy for mortality compared to APRI (AUC 0.746 vs. 0.595; p = 0.002) and CT severity score (AUC 0.490; p = 0.001), while performing comparably to age alone (AUC 0.756; p = 0.870). Log-FIB-4 remained associated with mortality after adjustment for age (odds ratio 2.04, 95% CI 1.10–3.76) but not after further adjustment for C-reactive protein and creatinine (odds ratio 1.75, 0.86–3.55), whereas FIB-4 > 2.44 retained an age-adjusted odds ratio of 5.90 (2.20–15.83). Among patients discharged alive, FIB-4 was not associated with subsequent death. Admission FIB-4 was independently associated with three-year mortality and outperformed APRI and the CT severity score, but its prognostic information largely overlapped with age; it should be regarded as a composite admission risk index whose added value requires external validation.